The Secretary of Energy Advisory Board
National Ignition Facility Laser System Task Force

Members:
John P. McTague (Chairman)
Andrew Athy (Chairman, SEAB)
Robert Byer
Gail McCarthy
Lawrence Papay
Burton Richter
Rochus Vogt
John Warlaumont

c/o Betsy Mullins, Executive Director, SEAB
U.S. Department of Energy
1000 Independence Avenue, SW
Washington, DC 20585

December 9, 1999

Members of the NIF Laser System Task Force:

On behalf of the Natural Resources Defense Council, Inc. (NRDC), we are submitting further written comments to the Secretary of Energy Advisory Board National Ignition Facility Laser System Task Force (herein referred to as the "SEAB NIF Task Force"). We are primarily responding to Lawrence Livermore National Laboratory and DOE Defense Program’s presentations to the SEAB NIF Task Force on November 15-16, 1999.

The November 15 & 16 presentations showed many photographs of the NIF construction site, perhaps creating the impression that the project is far along. This is in fact not the case. It is clear that Livermore has not yet purchased most of the laser components, and for many of these components the engineering drawings are still in development. Even fairly simple components to acquire, such as the capacitor banks, are just now in the purchase stage. Lacking from the Livermore and DOE presentations was a comprehensive table listing the major components of the NIF, their original costs, dates of purchase, delivery, and Livermore’s current estimates of cost and dates of purchase and delivery, so that the SEAB NIF Task Force could understand the overall state of the project. Such a table or its equivalent should be fundamental to any competent management of a project, and should have been the central theme in a presentation to any outside panel review. NRDC recommends that the SEAB NIF Task Force request that Livermore or DOE provide such a table.

John Murray, LLNL NIF Project Senior Scientist, gave a briefing on November 16, 199 entitled: "Laser System Performance Requirements and Architecture." One of Murray’s viewgraphs (see Attachment 1) shows the designed NIF ultra-violet (UV) laser fluence (energy/area) on optical components to be 8 J/m2, and this viewgraph shows that damage to fused silica occurs above 12 J/cm². These figures are not in agreement with the results given in a December 22, 1998 LLNL report: "Laser Damage Performance of Fused Silica Optical Components Measured on the Beamlet Laser at 351 nm (UCRL-JC-131221, see Attachment 2)." In Figure 7 of this report the damage to fused silica begins at 4 J/cm², well below the NIF design point. The authors note that this result was surprising, and they claim that it is probably fundamental to their system. Since the safe operating point of the NIF is actually 4 J/cm², then the laser output is limited to 0.9 MJ, well below the requirement for any ignition target. The alternative is to operate at higher levels and frequently replace the optics at an unknown operating cost.

The SEAB NIF Task Force should examine the proposed spatial filter for the NIF. The NIF spatial filter design point was changed from 100 micro-radians to 150 micro-radians because of filter closure problems. (See Attachment 3: "Spatial Filter Issues" by J. Murray et al, UCRL-JC-129751, July 23, 1998.) The resulting high spatial frequency noise will cause damage to the laser optics, reduce the frequency conversion, and lead to a halo at the target which could interfere with the laser-target coupling and target performance. We note for the Task Force that in Murray’s 1998 report on the spatial filter issue, he failed to note that the laser glass in Beamlet was not produced using the cheaper continuous melt process intended for NIF, and that a reduced optical quality of the glass could cause further problems.

In their presentations, Livermore Lab reaffirmed that ignition of a fusion target is the primary goal of the NIF project, and that Livermore calculations that 1.8 MJ of frequency-tripled laser light will be required to reach that goal. It is important to hold Livermore to this primary goal as the SEAB NIF Task Force weighs the costs and benefits associated with continuing the NIF project. If one likens the NIF to a car, then the chassis is 80% complete but it is unclear -- indeed doubtful -- whether the engine will propel the car very fast and at what sticker price. In the coming weeks as the SEAB NIF Task Force prepares its interim report on the NIF project, we stress that it would be best, in terms of public accountability regarding a major federal project and the future of the Science-Based Stockpile Stewardship Program, if the Task Force would issue a brutally honest picture of the current status of the NIF project in addition to whatever recommendations are made. In light of its many unresolved difficulties and escalating cost, NRDC advocates a stop work order and an intensive scientific and technical review of the NIF project.

Sincerely,